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Type-safe access to Java system properties
/*
// Licensed to Julian Hyde under one or more contributor license
// agreements. See the NOTICE file distributed with this work for
// additional information regarding copyright ownership.
//
// Julian Hyde licenses this file to you under the Apache License,
// Version 2.0 (the "License"); you may not use this file except in
// compliance with the License. You may obtain a copy of the License at:
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
*/
package org.eigenbase.util.property;
import java.util.*;
/**
* Definition and accessor for an integer property.
*
* @author jhyde
* @version $Id$
* @since May 4, 2004
*/
public class IntegerProperty
extends Property
{
//~ Instance fields --------------------------------------------------------
private final int minValue;
private final int maxValue;
//~ Constructors -----------------------------------------------------------
/**
* Creates an Integer property. Minimum and maximum values are set to {@link
* Integer#MIN_VALUE} and {@link Integer#MAX_VALUE}.
*
* @param properties Properties object which holds values for this property.
* @param path Name by which this property is serialized to a properties
* file, for example "com.acme.trace.Verbosity".
* @param defaultValue Default value.
*/
public IntegerProperty(
Properties properties,
String path,
int defaultValue)
{
this(
properties,
path,
defaultValue,
Integer.MIN_VALUE,
Integer.MAX_VALUE);
}
/**
* Creates an Integer property which has no default value. Minimum and
* maximum values are set to {@link Integer#MIN_VALUE} and {@link
* Integer#MAX_VALUE}.
*
* @param properties Properties object which holds values for this property.
* @param path Name by which this property is serialized to a properties
* file, for example "com.acme.trace.Verbosity".
*/
public IntegerProperty(
Properties properties,
String path)
{
this(properties, path, Integer.MIN_VALUE, Integer.MAX_VALUE);
}
/**
* Creates an Integer property with a default value and fixed minimum and
* maximum values.
*
* @param properties Properties object which holds values for this property.
* @param path Name by which this property is serialized to a properties
* file, for example "com.acme.trace.Verbosity".
* @param defaultValue Default value.
* @param minValue the minimum value of this property (inclusive)
* @param maxValue the maximum value of this property (inclusive)
*
* @throws IllegalArgumentException if defaultValue is not in
* the range [minValue, maxValue].
*/
public IntegerProperty(
Properties properties,
String path,
int defaultValue,
int minValue,
int maxValue)
{
super(
properties,
path,
Integer.toString(defaultValue));
if (minValue > maxValue) {
int temp = minValue;
minValue = maxValue;
maxValue = temp;
}
if ((defaultValue < minValue) || (defaultValue > maxValue)) {
throw new IllegalArgumentException(
"invalid default value " + defaultValue);
}
this.minValue = minValue;
this.maxValue = maxValue;
}
/**
* Creates an Integer property with fixed minimum and maximum values.
*
* @param properties Properties object which holds values for this property.
* @param path Name by which this property is serialized to a properties
* file, for example "com.acme.trace.Verbosity".
* @param minValue the minimum value of this property (inclusive)
* @param maxValue the maximum value of this property (inclusive)
*/
public IntegerProperty(
Properties properties,
String path,
int minValue,
int maxValue)
{
super(properties, path, null);
if (minValue > maxValue) {
int temp = minValue;
minValue = maxValue;
maxValue = temp;
}
this.minValue = minValue;
this.maxValue = maxValue;
}
//~ Methods ----------------------------------------------------------------
/**
* Retrieves the value of this integer property according to these rules.
*
*
* - If the property has no value, returns the default value.
* - If there is no default value and {@link #minValue} <= 0 <=
* {@link #maxValue}, returns 0.
* - If there is no default value and 0 is not in the min/max range,
* returns {@link #minValue}.
*
*/
public int get()
{
final String value = getInternal(null, false);
if (value == null) {
return noValue();
}
int v = Integer.parseInt(value);
// need to limit value in case setString() was called directly with
// an out-of-range value
return limit(v);
}
/**
* Retrieves the value of this integer property. If the property has no
* value, returns the default value. If there is no default value, returns
* the given default value. In all cases, the returned value is limited to
* the min/max value range given during construction.
*/
public int get(int defaultValue)
{
final String value =
getInternal(
Integer.toString(defaultValue),
false);
if (value == null) {
return limit(defaultValue);
}
int v = Integer.parseInt(value);
return limit(v);
}
/**
* Sets the value of this integer property. The value is limited to the
* min/max range given during construction.
*
* @return the previous value, or if not set: the default value. If no
* default value exists, 0 if that value is in the range [minValue,
* maxValue], or minValue if 0 is not in the range
*/
public int set(int value)
{
String prevValue = setString(Integer.toString(limit(value)));
if (prevValue == null) {
prevValue = getDefaultValue();
if (prevValue == null) {
return noValue();
}
}
int v = Integer.parseInt(prevValue);
return limit(v);
}
/**
* Returns value limited to the range [minValue, maxValue].
*
* @param value the value to limit
*
* @return value limited to the range [minValue, maxValue].
*/
private int limit(int value)
{
return Math.min(
Math.max(value, minValue),
maxValue);
}
/**
* Returns 0 if that value is in the range [minValue, maxValue]. Otherwise,
* returns minValue.
*/
private int noValue()
{
if ((minValue <= 0) && (maxValue >= 0)) {
return 0;
} else {
return minValue;
}
}
}
// End IntegerProperty.java